In a patient with primary adrenal insufficiency presenting with two weeks of fever and fatigue, marked leukocytosis, clean urinalysis, CT abdomen/pelvis showing diffuse mural thickening of the colon consistent with colitis, no abdominal pain, and negative chest X‑ray, what is the appropriate initial management?

Management of Suspected Adrenal Crisis in a Patient with Addison's Disease

This patient requires immediate treatment for adrenal crisis with intravenous hydrocortisone 100 mg bolus followed by 100 mg every 6-8 hours, plus aggressive fluid resuscitation with isotonic saline at 1 L/hour initially, while simultaneously investigating and treating the underlying infectious colitis. 1

Immediate Management Algorithm

Step 1: Treat Adrenal Crisis First (Do Not Delay)

The presence of fever, fatigue, and marked leukocytosis (WBC 19.36) in a patient with known Addison's disease represents a potential adrenal crisis triggered by infection, even without classic abdominal pain 1. Treatment must never be delayed by diagnostic procedures 1.

Immediate interventions:

• Hydrocortisone 100 mg IV/IM bolus immediately 1
• Continue hydrocortisone 100 mg IV/IM every 6-8 hours until clinical recovery 1
• Isotonic (0.9%) saline 1 L over first hour, then continue at slower rate for 24-48 hours with frequent hemodynamic monitoring 1
• Draw blood for cortisol, ACTH, electrolytes, glucose, and cultures before giving hydrocortisone if possible, but do not delay treatment 1

Step 2: Address the Precipitating Infection

The CT findings of diffuse colonic mural thickening with fever and leukocytosis indicate infectious or inflammatory colitis as the likely precipitant of adrenal crisis 1. Infections are the most common triggers of adrenal crisis in patients with primary adrenal insufficiency 1.

Diagnostic workup for colitis:

• Stool studies: C. difficile toxin, bacterial culture, ova and parasites
• Blood cultures (given fever and leukocytosis)
• Consider flexible sigmoidoscopy once hemodynamically stable if diagnosis remains unclear

Empiric antibiotic therapy should be initiated based on clinical suspicion while awaiting culture results, as untreated infection can perpetuate the adrenal crisis 1.

Step 3: Monitor and Adjust Treatment

Critical monitoring parameters:

• Hemodynamic status every 1-2 hours initially
• Serum electrolytes every 4-6 hours (watch for hyponatremia, hyperkalemia)
• Fluid balance to avoid overload 1
• Clinical improvement: resolution of fever, improved energy, hemodynamic stability

Tapering strategy:

• Continue parenteral hydrocortisone 100 mg every 6-8 hours until patient is clinically stable and able to eat/drink 1
• Taper to oral hydrocortisone at double the usual maintenance dose for 24-48 hours 1
• Return to normal maintenance dose (typically 15-25 mg daily in split doses) 1
• Restart fludrocortisone when hydrocortisone dose falls below 50 mg/day 1

Key Clinical Pitfalls to Avoid

The absence of abdominal pain does not exclude serious pathology in patients with adrenal insufficiency. The colitis may be relatively painless due to the anti-inflammatory effects of stress-dose glucocorticoids once treatment begins, or the patient may have altered pain perception.

Do not withhold stress-dose steroids because the patient "doesn't look that sick." Patients with Addison's disease cannot mount an appropriate cortisol response to physiologic stress (infection, inflammation), and even moderate illness can precipitate crisis 1, 2.

Mineralocorticoid replacement is temporarily unnecessary during acute crisis management because high-dose hydrocortisone (≥50 mg/day) provides sufficient mineralocorticoid activity by saturating the mineralocorticoid receptor 1.

Special Considerations for Invasive Procedures

If colonoscopy or other invasive bowel procedures are needed for definitive diagnosis of the colitis, the patient requires hospital admission with 100 mg hydrocortisone IM and fluids, with repeat dosing before the procedure 1. Given the current acute illness, maintain stress-dose coverage throughout.

Underlying Diagnosis

The diffuse colonic mural thickening most likely represents:

1. Infectious colitis (bacterial, C. difficile, CMV if immunocompromised)
2. Inflammatory bowel disease (though less likely as new diagnosis)
3. Ischemic colitis (less likely given age and lack of vascular risk factors mentioned)

The marked leukocytosis (19.36) strongly suggests bacterial infection or severe inflammation requiring antimicrobial therapy alongside adrenal crisis management.